Prevalence of Schistosoma mansoni-Salmonella coinfection among patients in southern Ethiopia

Beyond schistosomiasis: unraveling co-infections and altered immunity

Schistosomiasis is a neglected tropical disease caused by the helminth Schistosoma spp. and has the second highest global impact of all parasites. Schistosoma are transmitted through contact with contaminated fresh water predominantly in Africa, Asia, the Middle East, and South America. Due to the widespread prevalence of Schistosoma, co-infection with other infectious agents is common but often poorly described. Herein, we review recent literature describing the impact of Schistosoma co-infection between species and Schistosoma co-infection with blood-borne protozoa, soil-transmitted helminths, various intestinal protozoa, Mycobacterium, Salmonella, various urinary tract infection-causing agents, and viral pathogens. In each case, disease severity and, of particular interest, the immune landscape, are altered as a consequence of co-infection. Understanding the impact of schistosomiasis co-infections will be important when considering treatment strategies and vaccine development moving forward.

Can haematological changes constitute a surrogate diagnostic parameter to detect schistosomiasis in migrants and travellers? - A retrospective analysis

Background

Earlier studies found characteristic haematological changes in African patients with active schistosomiasis. If consistently present, full blood counts (FBC) may be helpful to diagnose schistosomiasis also in migrants and returning travellers.

Methods

A retrospective patient record review was conducted on data from seven European travel clinics, comparing FBC of Schistosoma egg-positive travellers and migrants to reference values. Sub-analyses were performed for children, returned travellers, migrants and different Schistosoma species.

Results

Data analysis included 382 subjects (median age 21.0 years [range 2-73]). In returned travellers, decreases in means of haemoglobin particularly in females (β = -0.82 g/dL, p = 0.005), MCV (β = -1.6 fL, p = 0.009), basophils, neutrophils, lymphocytes and monocytes (β = -0.07, p < 0.001; -0.57, p = 0.012; -0.57, p < 0.001 and -0.13 10³/μL, p < 0.001, respectively) were observed. As expected, eosinophils were increased (β = +0.45 10³/μL, p < 0.001). In migrants, a similar FBC profile was observed, yet thrombocytes and leukocytes were significantly lower in migrants (β = -48 10³/μL p < 0.001 and β = -2.35 10³/μL, p < 0.001, respectively).

Conclusions

Active egg-producing Schistosoma infections are associated with haematological alterations in returned travellers and migrants. However, these differences are discrete and seem to vary among disease stage and Schistosoma species. Therefore, the FBC is unsuitable as a surrogate diagnostic parameter to detect schistosomiasis.

Salmonella typhimurium exacerbates injuries but resolves fibrosis in liver and spleen during Schistosoma mansoni infection

BACKGROUND

In most developing or undeveloped countries, patients are often co-infected with multiple pathogens rather than a single pathogen. While different pathogens have their impact on morbidity and mortality, co-infection of more than one pathogen usually made the disease outcome different. Many studies reported the co-infection of Schistosoma with Salmonella in pandemic areas. However, the link or the underlying mechanism in the pathogenesis caused by Schistosoma-Salmonella co-infection is still unknown.

METHODS

In this study, Salmonella typhimurium (S. typhimurium) was challenged to Schistosoma mansoni (S. mansoni)-infected mice. Further experiments such as bacterial culture, histopathological examination, western blotting, and flow cytometry were performed to evaluate the outcomes of the infection. Cytokine responses of the mice were also determined by ELISA and real-time quantitative PCR.

RESULTS

Our results demonstrated that co-infected mice resulted in higher bacterial excretion in the acute phase but higher bacterial colonization in the chronic phase. Lesser egg burden was also observed during chronic schistosomiasis. Infection with S. typhimurium during schistosomiasis induces activation of the inflammasome and apoptosis, thereby leading to more drastic tissue damage. Interestingly, co-infected mice showed a lower fibrotic response in the liver and spleen. Further, co-infection alters the immunological functioning of the mice, possibly the reason for the observed pathological outcomes.

CONCLUSION

Collectively, our findings here demonstrated that S. mansoni-infected mice challenged with S. typhimurium altered their immunological responses, thereby leading to different pathological outcomes.

Magnitude of Malaria-Typhoid Fever Coinfection in Febrile Patients at Arba Minch General Hospital in Southern Ethiopia

BACKGROUND

Coinfection with malaria and typhoid fever is a major public health issue in developing countries. In endemic areas, including Ethiopia, people are at risk of acquiring both malaria and typhoid fever at the same time. Therefore, this study aimed to determine the magnitude of malaria-typhoid fever coinfection in febrile patients attending hospital at Southern Ethiopia.

METHODS

A hospital-based cross-sectional study was carried out on 416 febrile patients attending Arba Minch General Hospital from 1st October to 30th December 2021. The data was collected using a pretested structured questionnaire. Capillary and Venus blood samples were collected for assessing malaria and typhoid fever, respectively. Blood smear, culture, and biochemical tests were performed based on standard parasitological and microbiological methods. The P-value ≤ 0.05 was considered statistically significant.

RESULTS

The magnitude of malaria, typhoid fever, and their coinfections was 26.2% (109/416), 6.5% (27/416), and 3.1% (13/416), respectively. Among the confirmed malaria cases, about 66% of infections were Plasmodium falciparum. The malaria-typhoid fever coinfection showed a statistically significant association with a clinical presentation of a continuous pattern of fever (AOR = 5.84; 95% CI: 1.44-23.71, P = 0.014) and chills (AOR = 3.94; 95% CI: 1.04-14.89, P = 0.044). About 29.6% of Salmonella isolates were multidrug-resistant (MDR).

CONCLUSION

The total rate of coinfection with malaria and typhoid fever was comparable to that of previous studies. With the consideration of higher prevalence of drug resistance of Salmonella spp. and higher prevalence of malaria-typhoid fever coinfection, proper diagnostic procedure should be implemented for proper use of drugs.

Pathogenicity of Salmonella During Schistosoma-Salmonella Co-infections and the Importance of the Gut Microbiota

Antibiotic inefficacy in treating bacterial infections is largely studied in the context of developing resistance mechanisms. However, little attention has been paid to combined diseases mechanisms, interspecies pathogenesis and the resulting impact on antimicrobial treatment. This review will consider the co-infections of Salmonella and Schistosoma mansoni. It summarises the protective mechanisms that the pathophysiology of the two infections confer, which leads to an antibiotic protection phenomenon. This review will elucidate the functional characteristics of the gut microbiota in the context of these co-infections, the pathogenicity of these infections in infected mice, and the efficacy of the antibiotics used in treatment of these co-infections over time. Salmonella-Schistosoma interactions and the mechanism for antibiotic protection are not well established. However, antimicrobial drug inefficacy is an existing phenomenon in these co-infections. The treatment of schistosomiasis to ensure the efficacy of antibiotic therapy for bacterial infections should be considered in co-infected patients.